By ALFRED NEWTON.
Some facts as to the geographical distribution—whether of plants or animals—have, it is true, been long known, indeed they present themselves on the slightest inquiry. Every one is aware that elephants and tigers do not roam in our woods now-a-days, whatever may have been the case aforetime. Many persons have read that horses were unknown in the New World at the time of its discovery by Europeans, and were subsequently introduced by its Spanish conquerors. Some may even know that humming-birds are not to be found in the Old World, and that (as has been already said) the so-called “marsupial” animals are at the present time, with a few exceptions, confined to Australia, as well as that in that country nothing like vultures or woodpeckers are to be found.
The assemblage of animals which inhabit any portion of the earth’s surface, whether it be land or water, is called its “fauna,” in the same way that the plants of a country are called its “flora.” To be entitled to the former term it is unnecessary that the animals composing the assemblage should not be found anywhere else; it is enough that they occur there and impress upon the district, be it large or small, certain more or less well-marked peculiarities. Nor does it follow because certain kinds of animals are found to inhabit two districts that these two have the same fauna. We have to take the whole assemblage as a whole, and abide by the verdict which the majority of kinds affords us. Now by collecting such facts as those stated in the preceding paragraph, and such facts can be collected by the hundred or the thousand, we are able to get hold of a general idea of the geographical distribution of animals, and when the results of all the knowledge on this subject which we can acquire are brought together, it will appear that the earth may be partitioned into several great zoölogical regions—each separable in subregions, provinces, subprovinces and so on.
America is divided into two regions—the “Nearctic” and the “Neotropical,” which meet in Mexico at about the 22d parallel of north latitude:—
(1) The Nearctic Region (that is the Northern part of the New World) includes the Aleutian Islands, besides Greenland and the Bermudas with all of what is generally called North America.
(2) The Neotropical Region (that is the tropical part of the New World) comprises the West India Islands, the Galapagos, and the whole of South and Central America.
Passing to the Old World, it is separable, as may be seen, into four regions.
(3) The Palæarctic Region (or Northern part of the Old World) including that portion of Africa which lies to the northward of the Great Desert, the Atlantic Islands (Madeiras, Canaries, and Azores), the whole of Europe from Iceland to Greece, besides Asia Minor, Palestine, Persia, probably Afghanistan, the whole of Northern, Central and Eastern Asia, lying to the northward of the Himalaya Mountains and of China proper, as well as Japan.
(4) The Ethiopian Region consists of Africa, excepting Morocco and Algeria (which, as already stated, belong to the preceding region), as well as of Arabia and of course the adjacent islands from those off the Cape Verd to Madagascar and Socotra.